Lighting apparatus

ABSTRACT

In recent years, much attention has been paid to a projection type display apparatus using a plurality of light sources, as projection type video equipment capable of large screen display. However, in an optical system using a plurality of light sources, devices are designed so that uniform lighting can be provided assuming only the use of all the light sources. Thus, the uniformity of brightness within a display screen may be degraded if not all of the plurality of light sources are used. A light apparatus includes a plurality of lamp unit sections, a synthetic mirror section that reflects and synthesizes lights generated by all or some of the plurality of lamp unit sections and, and a synthetic mirror section adjusting mechanism that holds the synthetic mirror section so that its position can be changed so as to adjust the reflecting optical paths of the reflected lights.

TECHNICAL FIELD

The present invention relates to, for example, a lighting apparatus thatprojects a large screen video on a screen.

BACKGROUND ART

In recent years, much attention has been paid to a projection typedisplay apparatus (projector) using a plurality of light sources, asprojection type video equipment capable of large screen display (referto, for example, Japanese Patent Laid-Open No. 2000-171901).

The entire disclosure of Japanese Patent Laid-Open No. 2001-171901 isincorporated herein by reference in its entirety.

These projection type display apparatuses (1) light a light modulatingelement (a transmission or reflection type liquid crystal or a DMD(Digital Micromirror Device) that can change a reflection directionusing micromirrors arranged in an array) capable of light modulation,utilizing light radiated by a light source, (2) form an optical image onthe light modulating element in accordance with an externally suppliedvideo signal, and (3) use a projection lens to enlarge and project theoptical image on a screen, the image being illumination light modulatedby the light modulating element.

(A) An important optical characteristic of enlarged projective displayon a large screen is the uniformity of brightness within the displayscreen.

For the uniformity of brightness within a display area, it is importantthat the light modulating element is irradiated with light generated bya lamp as a luminous flux that has a relatively uniform brightness in acentral and peripheral portions of the area. That is, it is importantthat the brightness of a luminous flux is uniform.

FIGS. 10 and 11 show a conventional lighting apparatus using a pluralityof light sources and implementing a projection type display apparatususing a transmission type liquid crystal panel as a light modulatingelement and a projection lens.

FIG. 10 shows an optical system using lens arrays 122 and 123 in which aplurality of lenses are two-dimensionally arranged, as an opticalelement called an integrator and enabling uniform lighting. Furthermore,FIG. 11 shows an optical system using a square-pole-like glass rod 125as an integrator.

Light emitted by lamps 151 and 161 of these lighting apparatuses (seeFIGS. 10 and 11) is (1) collected by ellipsoidal mirrors (concavemirrors) 152 and 162, (2) emitted through openings in the ellipsoidalmirrors 152 and 162, and (3) reflected by a triangle-pole-like prism 131of a synthesis mirror section 130 that reflects a plurality of luminousfluxes in a predetermined direction, the prism 131 havingreflective-coated sides.

The flux reflected by the prism 131 has a nonuniform brightness and hasa large difference in luminance between the vicinity of the center andthe peripheral portion of the luminous flux.

Thus, in order to make uniform the luminance on the area to be lighted,the luminous flux reflected by the prism 131 is split into partialfluxes. Then, the partial fluxes are super imposed on the area to belighted to improve the uniformity of the illumination light.

If the lens arrays 122 and 123, in which a plurality of lenses aretwo-dimensionally arranged, are used (see FIG. 10) , a luminous fluxincident on a lighting unit section 120 is made almost parallel with theoptical axis of the lighting unit section 120 by a relay lens 121. Thefluxes are then split into partial fluxes by the lens array 122, inwhich a plurality of first lenses are two-dimensionally arranged. Then,owing to the lens array 123, which has lenses corresponding to theindividual lenses in the lens array 122, the partial fluxes then formimages similar to respective lens openings in the lens array 122 and arethen superimposed on an area of a light receiving section 110 which isto be lighted.

The luminous flux having nonuniform brightness when entering the lensarray 122 is split into the partial fluxes having different luminancedistributions. The partial fluxes are then superimposed. In this manner,lighting is achieved which has improved uniformity within the area to belighted.

If the square-pole-like glass rod 125 is used (see FIG. 11), a luminousflux incident on the lighting unit section 120 enters a facet of theglass rod 125. The light entering the interior of the glass rod 125 isemitted from a facet of the glass rod 125 which is opposite its entryfacet while being transmitted through the glass rod 125 or being totallyreflected. At this time, the light emitted from the exit facet istotally reflected inside the glass rod 125 a number of timescorresponding to the angle at which the light has been incident on theglass rod 125. Accordingly, the partial fluxes are emitted from oneopening, the exit facet of the glass rod 125, at different angles. Thepartial fluxes are superimposed by a relay lens 124 on the area of lightreceiving section 110 which is to be lighted.

The luminous flux having nonuniform brightness when entering the glassrod 125 is split into the partial fluxes having different luminancedistributions. The partial fluxes are then superimposed. In this manner,lighting is achieved which has improved uniformity within the area to belighted.

Thus, a projection type display apparatus using the lighting apparatus(see FIGS. 10 and 11) can display a video with a highly uniformbrightness by enlarging an image formed by a liquid crystal panel (notshown) arranged on a lighted surface as a light modulating element, on ascreen (not shown) via a projection lens (not shown)

(B) FIG. 12 shows a lighting apparatus system configured similarly tothe above lighting apparatuses and using nine lighting apparatuses 300to project light from behind a transmission type multiscreen 500 so thatthe multiscreen 500 can form one integrated video on a screen.

By utilizing the lighting apparatus system (see FIG. 12) that displaysone integrated video using the plurality of lighting apparatuses 300, itis possible to display videos of higher resolutions or simultaneouslydisplay many pieces of information.

(A) The inventors have found that with an optical system using aplurality of light sources as described above, not all the plural lightsources may be simultaneously used and some of the plural light sourcesmay be used in accordance with a user's manual operation.

More specifically, high-pressure mercury lamps that are light sourcesoften used in lighting apparatuses have a lifetime of about 2,000 to5,000 hours, which is relatively shorter than that of a set, which isabout 5 to 10 years. Thus, if no particular requests have been made forthe brightness in the display screen or the time remaining before thelamps must be replaced is to be maximized, some of the plural lightsources are often used.

Furthermore, if a plurality of light sources are used but trouble occurssuch as the sudden breakage of any lamp or a failure to light any lamp,some of the plural light sources are used.

However, in an optical system using a plurality of light sources, thedevices are designed so as to provide uniform lighting assuming theusage of all the light sources. In short, with an optical system using aplurality of light sources, the uniformity of the brightness in thedisplay screen may be degraded if not all the plural light sources areused.

(B) The inventors have also found that with a lighting apparatus systemthat displays one integrated video using a plurality of lightingapparatuses, the brightness may vary in a wavy form within oneintegrated video as shown in FIG. 13.

More specifically, the 3×3 multiscreen 500 has the brightest part in acentral portion of a small screen corresponding to each lightingapparatus and the darkest part in a peripheral portion of the smallscreen. Accordingly, in one integrated video, (1) the brightnessdistribution in the direction of a vertical axis is shaped likemountains having three peaks as shown in a graph 601, while (2) thebrightness distribution in the direction of a horizontal axis is shapedlike mountains having three peaks as shown in a graph 602.

However, such a variation in brightness in a wavy form within oneintegrated video may result in an esthetically unfavorable impression onmany users. In short, a lighting apparatus system that displays oneintegrated video using a plurality of lighting apparatuses may have adegraded display grade.

DISCLOSURE OF THE INVENTION

In view of the above conventional problems, it is an object of thepresent invention to provide a lighting apparatus that can improve thedisplay quality of projective display.

A first invention of the present invention is a lighting apparatuscomprising:

-   -   a plurality of light sources generating light;    -   light reflecting and synthesizing means of reflecting and        synthesizing lights generated by all or some of said plurality        of light sources; and    -   light reflecting and synthesizing means holding means of holding        said light reflecting and synthesizing means so that a position        of said light reflecting and synthesizing means can be changed        so as to adjust reflecting optical paths of said reflected        lights.

A second invention of the present invention is the lighting apparatusaccording to the first invention of the present invention, furthercomprising light superimposing means of superimposing said reflectedlights on each other, and light intensity distribution measuring meansof measuring intensity distribution of said superimposed light,

-   -   wherein said adjustment is carried out on the basis of a result        of said measurement.

A third invention of the present invention is the lighting apparatusaccording to the first invention of the present invention, furthercomprising light rotating means of rotating said reflected lights.

A fourth invention of the present invention is the lighting apparatusaccording to the first invention of the present invention, wherein saidlight reflecting and synthesizing means is constructed utilizing a prismor a mirror.

A fifth invention of the present invention is the lighting apparatusaccording to the second invention of the present invention, wherein saidlight superimposing means is constructed utilizing a lens array or aglass rod.

A sixth invention of the present invention is a lighting apparatussystem comprising a plurality of lighting apparatuses according to thefirst invention of the present invention,

-   -   wherein the position of said light reflecting and synthesizing        means of each of the lighting apparatuses is changed so as to        meet a predetermined relationship.

A seventh invention of the present invention is a lighting methodcomprising:

-   -   a light reflecting and synthesizing means holding step of        holding light reflecting and synthesizing means of reflecting        and synthesizing lights generated by all or some of a plurality        of light sources so that a position of said light reflecting and        synthesizing means can be changed so as to adjust reflecting        optical paths of said reflected lights; and    -   a reflecting optical path adjusting step of adjusting the        reflecting optical paths of said reflected lights.

An eighth invention of the present invention is a lighting methodaccording to the seventh invention of the present invention, furthercomprising a light superimposing step of superimposing said reflectedlights on each other, and a light intensity distribution measuring stepof measuring intensity distribution of said superimposed lights,

-   -   wherein said adjustment is carried out on the basis of a result        of said measurement.

A ninth invention of the present invention is a program allowing acomputer to execute the reflecting optical path adjusting step of thelighting method according to the seventh invention of the presentinvention.

A tenth invention of the present invention is a recording mediumcarrying the program according to the ninth invention of the presentinvention wherein the recording medium can be processed by a computer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the configuration of a lightingapparatus of Embodiment 1 according to the present invention;

FIG. 2 is a schematic plan view illustrating directions adjusted by asynthetic mirror section adjusting mechanism 140 of Embodiment 1according to the present invention;

FIG. 3 is a schematic diagram showing the configuration of the syntheticmirror section adjusting mechanism of the lighting apparatus of oneembodiment according to the present invention;

FIG. 4 is a schematic diagram showing the configuration of a lightingapparatus of one embodiment according to the present invention;

FIG. 5 is a schematic diagram showing the configuration of a lightingapparatus of one embodiment according to the present invention;

FIG. 6 is a schematic diagram showing the configuration of a lightingapparatus of one embodiment according to the present invention;

FIG. 7 is a schematic diagram showing the configuration of a lightingapparatus of one embodiment according to the present invention;

FIG. 8 is a schematic diagram showing the configuration of a lightingapparatus of one embodiment according to the present invention;

FIG. 9 is a diagram illustrating a projection type display apparatus ofEmbodiment 2 according to the present invention and projective displayprovided by the projection type display apparatus;

FIG. 10 is a schematic diagram showing the configuration of aconventional lighting apparatus;

FIG. 11 is a schematic diagram showing the configuration of aconventional lighting apparatus;

FIG. 12 is a diagram showing a conventional lighting apparatus system;and

FIG. 13 is a diagram illustrating projective display provided by theconventional lighting apparatus system.

DESCRIPTION OF SYMBOLS

-   110 Light receiving section-   120 Lighting unit section-   121 Relay lens-   122 Lens array-   123 Lens array-   124 Relay lens-   130 Synthetic mirror section-   131 Prism-   140 Synthetic mirror section adjusting mechanism-   150 Lamp unit section-   151 Lamp-   152 Ellipsoidal mirror-   160 Lamp unit section-   161 Lamp-   162 Ellipsoidal mirror

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments according to the present invention will be described belowwith reference to the drawings.

EMBODIMENT 1

First, with reference to FIG. 1 that is a schematic diagram showing theconfiguration of a lighting apparatus of Embodiment 1 according to thepresent invention, description will be given of the configuration of thelighting apparatus of the present embodiment.

The lighting apparatus of the present embodiment comprises lamp unitsections 150 and 160, a synthetic mirror section adjusting mechanism140, a synthetic mirror section 130, a lighting unit section 120, and alight receiving section 110.

The lighting apparatus of the present embodiment is characterized bycomprising a synthetic mirror section adjusting mechanism 140.

Now, a further detailed description will be given of the configurationof the lighting apparatus of the present embodiment.

The lamp unit section 150 is means having an ultrahigh-pressure mercurylamp 151 having a glass tube in which an inert gas or the like is sealedin order to form an illuminant by arc discharge, and an ellipsoidalmirror 152. A light emitting section of the lamp 151 is arranged at afirst focus of the ellipsoidal mirror 152.

The lamp unit section 160 is means configured similarly to the lamp unitsection 150 and having a lamp 161 and an ellipsoidal mirror 162. A lightemitting section of the lamp 161 is arranged at a first focus of theellipsoidal mirror 162.

The lamp unit sections 150 and 160 are light sources that are normallylighted at all times. The lamp unit sections 150 and 160 are arranged sothat (1) the optical axis of the lamp unit section 150 coincides withthe optical axis of the lamp unit section 160, that (2) the optical axisof the lamp unit section 150 (that is, the optical axis of the lamp unitsection 160) is generally orthogonal to the optical axis of the lightingunit section 120, and that (3) a second focus of the ellipsoidal mirror152 and a second focus of the ellipsoidal mirror 162 substantiallycoincide with a reflection surface of the prism 131. The optical axesare shown with alternate long and short dash lines, with theillustration of the foci omitted.

The synthetic mirror section 130 is means having a triangular-pole-likeprism 131 having sides acting as mirror surfaces that reflect luminousfluxes emitted by the lamp unit sections 150 and 160, toward thelighting unit section 120, the sides being coated with a reflection filmsuch as a metal reflection film or a dielectric multilayer film.

The sides of the prism 131 are arranged near the second focus of theellipsoidal mirror 152 (that is, near the second focus of theellipsoidal mirror 162).

The synthetic mirror section adjusting mechanism 140 is means of movingand adjusting the position of the synthetic mirror section 130 so that abottom surface of the prism 131 is kept parallel with a plane containingthe optical axis of the lamp unit section 150 and the optical axis ofthe lighting unit section 120, the two optical axes being orthogonal toeach other.

The movement of the synthetic mirror section 130 is the synthesis ofparallel movement parallel with the plane containing the optical axis ofthe lamp unit section 150 and the optical axis of the lighting unitsection 120 and rotative movement with respect to the normal of theplane containing the optical axis of the lamp unit section 150 and theoptical axis of the lighting unit section 120.

A further detailed description will be given of the roles of thesynthetic mirror section adjusting mechanism 140 that is acharacteristic component of the lighting apparatus of the presentembodiment.

The lighting unit section 120 is means having relay lenses 121 and 124that enable the shaping and homogenization of a luminous flux on thebasis of a lighted area, and lens arrays 122 and 123 acting asintegrators to enable highly uniform lighting.

The lens array 122 has a plurality of two-dimensionally arranged firstlenses. The lens array 123 has a plurality of two-dimensionally arrangedsecond lenses corresponding to the individual first lenses in the lensarray 122.

The lamp unit sections 150 and 160 correspond to light sources of thepresent invention. The synthetic mirror section 130 corresponds to lightreflecting and synthesizing means of the present invention. Thesynthetic mirror section adjusting mechanism 140 corresponds to lightreflecting and synthesizing means holding means of the presentinvention. The lighting unit section 120 corresponds to lightsuperimposing means of the present invention. The lighting apparatus ofthe present embodiment corresponds to a lighting apparatus of thepresent invention.

Now, with reference to mainly FIG. 1, description will be given tooperations of the lighting apparatus of the present embodiment.

While describing operations of the lighting apparatus of the presentembodiment, description will be given of an embodiment of a lightingmethod of the present invention.

The synthetic mirror section adjusting mechanism 140 adjusts theposition of the synthetic mirror section 130 to a neutral one (whereuniform lighting can be provided assuming that both lamps 151 and 161are used and which is shown utilizing dot lines in FIG. 2, describedlater) so that a symmetrical surface of the prism 131 (a symmetricalsurface perpendicular to the bottom surface) is generally orthogonal tothe optical axes of the lamp unit sections 150 and 160 and contains theoptical axis of the lighting unit section 120.

The lamp 151 emits light generated by arc discharge, from the vicinityof the first focus of the ellipsoidal mirror 152. The ellipsoidal mirror152 condenses light emitted from the vicinity of the first focus of theellipsoidal mirror 152 to form a small light spot on a side of the prism131 and near the second focus of the ellipsoidal mirror 152, the sidebeing is closer to the lamp unit section 150. The prism 131 reflects thelight formed as the small spot near the second focus of the ellipsoidalmirror 152 by the condensation, from the light spot along the opticalaxis of the lighting unit section 120.

Similarly, the lamp 161 emits light generated by arc discharge, from thevicinity of the first focus of the ellipsoidal mirror 162. Theellipsoidal mirror 162 condenses light emitted from the vicinity of thefirst focus of the ellipsoidal mirror 162 to form a small light spot ona side of the prism 131 and near the second focus of the ellipsoidalmirror 162, the side being is closer to the lamp unit section 160. Theprism 131 reflects the light formed as the small spot near the secondfocus of the ellipsoidal mirror 162 by the condensation, from the lightspot along the optical axis of the lighting unit section 120.

The relay lens 121 converts the light reflected along the optical axisof the lighting unit section 120, into a luminous flux generallyparallel with the optical axis of the lighting unit section 120 so thatthe flux does not spread outward.

The lens array 122 utilizes the plurality of first lenses to split theluminous flux generally parallel with the optical axis of the lightingunit section 120, into partial fluxes.

The lens array 123 utilizes the plurality of second lenses and the relaylens 124 to form the split partial fluxes into images similar torespective lens openings of the lens array 122. The images aresuperimposed on one another on the light receiving section 110.

Thus, the luminous flux having nonuniform brightness is split intopartial fluxes having various luminance distributions. The split partialfluxes are then superimposed on one another to provide uniform lightingwithin the area to be lighted.

Now, a detailed description will be given of the roles of the syntheticmirror section adjusting mechanism 140, which is a characteristiccomponent of the lighting apparatus of the present embodiment.

(A) The lamps 151 and 161 are not simultaneously used if no particularrequests have been made for the brightness in the display screen, thetime remaining before the lamps must be replaced is to be maximized, ortrouble occurs such as the sudden breakage of any lamp or a failure tolight any lamp, as described previously.

On this occasion, the synthetic mirror section adjusting mechanism 140moves the synthetic mirror section 130 to adjust its position.

More specifically, as shown in FIG. 2 that is a schematic plan viewillustrating directions adjusted by the synthetic mirror sectionadjusting mechanism 140 of Embodiment 1 according to the presentinvention, when only the lamp 151 is used and the lamp 161 is not used,the synthetic mirror section adjusting mechanism 140 (not shown in FIG.2) shifts the synthetic mirror section 130 from the previously describedneutral position (1) toward the lamp unit section 160 along the opticalaxis of the lamp unit section 150, shown by arrow A. The syntheticmirror section adjusting mechanism 140 also shifts the synthetic mirrorsection 130 from the previously described neutral position 2) toward thelighting unit section 120 along the optical axis of the lighting unitsection 120, shown by arrow B.

Since the position of the synthetic mirror section 130 is thus adjusted,the relay lens 121 can convert light from the lamp 151 reflected by theprism 131 along the optical axis of the lighting unit section 120, intoa luminous flux parallel with the optical axis of the lighting unitsection 120.

Thus, even if only the lamp 151 is used, highly uniform lighting can beprovided.

(B) In an actual optical system (in particular, an optical system usingan arc lamp or the like), a light emitting section in the glass tubesphere is deformed upward into an arch owing to the convection of theinert gas sealed in the glass tube sphere. This often prevents theformation of a brightness distribution rotationally symmetric withrespect to the optical axis.

Essentially, the respective lamps provide different outputs. It is thusunavoidable to undergo an error in the arrangement of the opticalelements, form tolerance, or a variation in the reflectivity ortransmittance within the surface of any mirror or lens. Accordingly,even if the devices are produced exactly as designed, perfectly uniformlighting (that is, such lighting as provides a lighted area having onlya small difference in luminance between its central portion andperipheral portion and having a luminance distribution rotationallysymmetric with respect to the optical axis) is rarely provided.

The previously described adjustment of the position of the syntheticmirror section 130 executed by the synthetic mirror section adjustingmechanism 140 is also effective in eliminating the nonuniformity of theluminance distribution within the lighted area.

(C) Furthermore, even if the lamps 151 and 161 provide different lampoutputs, the centers of the luminance distributions of the lamps 151 and161 are commonly present in the plane containing the optical axis of thelamp unit section 150 and the optical axis of the lighting unit section120. Thus, by moving the synthetic mirror section 130 so that the bottomsurface of the prism 131 is kept parallel with the plane containing theoptical axis of the lamp unit section 150 and the optical axis of thelighting unit section 120, it is possible to appropriately adjust theluminance distributions of the lamps 151 and 161 to considerably improvethe uniformity of lighting (in particular, the uniformity in thedirection of the optical axis of the lamp unit section 150).

Embodiment 1 has been described in detail.

(1) In the abode described present embodiment, a change in the positionof the light reflecting and synthesizing means of the present inventionis such movement of the synthetic mirror section 130 as keeps the bottomsurface of the prism 131 parallel with the plane containing the opticalaxis of the lamp unit section 150 and the optical axis of the lightingunit section 120.

However, the present invention is not limited to this aspect. A changein the position of the light reflecting and synthesizing means of thepresent invention may be such movement of the synthetic mirror section130 as inclines the bottom surface of the prism 131 relative to theplane containing the optical axis of the lamp unit section 150 and theoptical axis of the lighting unit section 120.

More specifically, such movement of the synthetic mirror section 130 maybe rotative movement around the optical axis of the lamp unit section150. Such rotative movement enables the appropriate adjustment of theluminance distributions of the lamps 151 and 161 even if the lamps 151and 161 have different heights from the plane containing the opticalaxis of the lamp unit section 150 and the optical axis of the lightingunit section 120. This serves to improve the uniformity of lighting (inparticular, the uniformity in the normal direction of the planecontaining the optical axis of the lamp unit section 150 and the opticalaxis of the lighting unit section 120).

Of course, a change in the position of the light reflecting andsynthesizing means of the present invention may be a combination of (a)such movement of the synthetic mirror section 130 as keeps the bottomsurface of the prism 131 parallel with the plane containing the opticalaxis of the lamp unit section 150 and the optical axis of the lightingunit section 120 and (b) such movement of the synthetic mirror section130 as inclines the bottom surface of the prism 131 relative to theplane containing the optical axis of the lamp unit section 150 and theoptical axis of the lighting unit section 120, as described above.

Now, an example of a specific configuration and operation of thesynthetic mirror section adjusting mechanism will be described withreference to FIG. 3 that is a schematic diagram showing theconfiguration of the synthetic mirror section adjusting mechanism of thelighting apparatus of one embodiment according to the present invention.

The synthetic mirror section 130 is fixed to a first moving substrate170. The first moving substrate 170 is arranged on a second movingsubstrate 171.

Projections 172 a and 172 b provided on the second moving substrate 171are fitted into slots 173 a and 173 b formed in the first movingsubstrate 170.

The first moving substrate 170 is moved in the direction orthogonal tothe direction of the optical axis of the lamp unit section 150 by amotor 177 by driving a reduction gear 175 composed of an integratedsmall and large gears meshing with a toothed portion 174 formed on aside of the first moving substrate 170 as well as a worm gear 176meshing with the reduction gear 175.

More specifically, when the reduction gear 175 is rotated by rotativedriving in one direction carried out by the motor 177, the first movingsubstrate 170 moves leftward on the second moving substrate 171. On theother hand, when the reduction gear 175 is rotated by rotative drivingin the other direction carried out by the motor 177, the first movingsubstrate 170 moves rightward on the second moving substrate 171.

Thus, the first moving substrate 170 can be moved on the second movingsubstrate 171 in the direction orthogonal to the direction of theoptical axis of the lamp unit section 150.

Furthermore, the second moving substrate 171 is placed on a third movingsubstrate 186.

The first moving substrate 170 is moved along the optical axis of thelamp unit section 150 by a motor 180 by driving a reduction gear 182composed of an integrated small and large gears meshing with a toothedportion 179 formed on an end surface of the second moving substrate 171as well as a worm gear 181 meshing with the reduction gear 182.

More specifically, when the reduction gear 182 is rotated by rotativedriving in one direction carried out by the motor 180, the first movingsubstrate 170 moves on a fixed substrate 178 away from the lamp unitsection 150 together with the second moving substrate 171. On the otherhand, when the reduction gear 182 is rotated by rotative driving in theother direction carried out by the motor 180, the first moving substrate170 moves on the fixed substrate 178 toward the lamp unit section 150together with the second moving substrate 171.

Thus, the first moving substrate 170 can be moved on the second movingsubstrate 171 along the optical axis of the lamp unit section 150.

The second moving substrate 171 is supported so as to be rotatablearound a support shaft 183 provided parallel with the optical axis ofthe lamp unit section 150.

A pin (not shown) moved upward and downward via a reduction mechanism185 by rotative driving by a motor 184 is abutted against the thirdmoving substrate 186 through a hole (not shown) formed below the fixedsubstrate 178.

Thus, the first moving substrate 170 can be rotated around the supportshaft 183 together with the second moving substrate 171 and the thirdmoving substrate 186.

As is apparent from the above description, the synthetic mirror sectionadjusting mechanism can spatially continuously move the prism 131 of thesynthetic mirror section 130.

(2) In the above described present embodiment, the light source of thepresent invention has the ultrahigh-pressure mercury lamps 151 and 161.However, the present invention is not limited to this aspect. The lightsource of the present invention may have a high-pressure mercury lamp,or a metal halide lamp, a xenon lamp, a halogen lamp, or the like whichis used as a lamp having a high light emission efficiency.

(3) Furthermore, in the above described present embodiment, the lightsource of the present invention has the two lamps 151 and 161. However,the present invention is not limited to this aspect. The light source ofthe present invention may have two or more lamps that are lighted in anarbitrary combination.

More specifically, as shown in FIG. 4 that is a schematic diagram of alighting apparatus of one embodiment according to the present invention,the present invention includes a lighting apparatus comprising, inaddition to the lamps 151 and 161, lamps 151′ and 161′ that are normallylighted at all times (that is, comprising a total of four lamps 151,161, 151′ and 161′).

Such a lighting apparatus comprises the lamp unit sections 150, 160,150′, and 160′, a synthetic mirror section adjusting mechanism 140′, asynthetic mirror section 130′, the lighting unit section 120, and thelight receiving section 110.

The lamp unit section 150′ is means configured similarly to the lampunit section 150 and having the lamp 151′ and an ellipsoidal mirror152′. A light emitting section of the lamp 151′ is arranged at a firstfocus of the ellipsoidal mirror 152′.

The lamp unit section 160′ is means configured similarly to the lampunit section 160 and having the lamp 161′ and an ellipsoidal mirror162′. A light emitting section of the lamp 161′ is arranged at a firstfocus of the ellipsoidal mirror 162′.

The lamp unit sections 150′ and 160′ are arranged so that (1) theoptical axis of the lamp unit section 150′ coincides with the opticalaxis of the lamp unit section 160′, that (2) the optical axis of thelamp unit section 150′ (that is, the optical axis of the lamp unitsection 160′) is generally orthogonal to the optical axis of thelighting unit section 120, and that (3) a second focus of theellipsoidal mirror 152′ and a second focus of the ellipsoidal mirror162′ substantially coincide with a reflection surface of a prism 131′.The optical axes are shown with alternate long and short dash lines,with the illustration of the foci omitted.

The optical axis of the lamp unit section 150 is generally orthogonal tothe optical axis of the lamp unit section 150′.

The synthetic mirror section 130′ is means having aquadratic-pyramid-like (pyramidal) prism 131′ having sides acting asmirror surfaces that reflect luminous fluxes emitted by the lamp unitsections 150, 160, 150′, and 160′ toward the lighting unit section 120,the sides being coated with a reflection film.

The sides of the prism 131′ are arranged near the second focus of theellipsoidal mirror 152 (that is, near the second focus of theellipsoidal mirror 162). The sides of the prism 131′ are also arrangednear the second focus of the ellipsoidal mirror 152′ (that is, near thesecond focus of the ellipsoidal mirror 162′).

The synthetic mirror section adjusting mechanism 140′ is means of movingand adjusting the position of the synthetic mirror section 130′ so thata bottom surface of the prism 131′ is kept parallel with a planecontaining the optical axis of the lamp unit section 150 and the opticalaxis of the lamp unit section 150′, the two optical axes beingorthogonal to each other.

The movement of the synthetic mirror section 130′ is the synthesis ofparallel movement parallel with the plane containing the optical axis ofthe lamp unit section 150 and the optical axis of the lamp unit section150′ and rotative movement with respect to the normal of the planecontaining the optical axis of the lamp unit section 150 and the opticalaxis of the lamp unit section 150′

The lamp unit sections 150, 160, 150′, and 160′ correspond to lightsources of the present invention. The synthetic mirror section 130′corresponds to light reflecting and synthesizing means of the presentinvention. The synthetic mirror section adjusting mechanism 140′corresponds to light reflecting and synthesizing means holding means ofthe present invention.

A specific example of a lighting apparatus comprising four lamps hasbeen described in detail. However, it is possible to implement alighting apparatus of the present invention comprising three or five ormore light sources by configuring the light reflecting and synthesizingmeans and the light reflecting and synthesizing means holding means ofthe present invention in accordance with the number of the lightsources.

(4) In the above described present embodiment, the light reflecting andsynthesizing means of the present invention has the prism 131. However,the present invention is not limited to this aspect. The lightreflecting and synthesizing means of the present invention may have (1)two mirrors laminated with each other at their edges or (2) two mirrorsthat are not laminated with each other at their edges (for example, amirror 1131 rotatively moved by a synthetic mirror section adjustingmechanism 1140 around an axis Z perpendicular to the plane containingthe optical axis of the lamp unit section 150 and the optical axis ofthe lighting unit section 120 and a mirror 1131′ rotatively moved by asynthetic mirror section adjusting mechanism 1140′ around an axis Z′perpendicular to the plane containing the optical axis of the lamp unitsection 160 and the optical axis of the lighting unit section 120, asshown in FIG. 5 that is a schematic diagram showing the configuration ofa lighting apparatus of one embodiment according to the presentinvention).

(5) In the above described present embodiment, the light source of thepresent invention has the ellipsoidal mirrors 152 and 162. However, thepresent invention is not limited to this aspect. The light source of thepresent invention may have parabolic mirrors.

(6) Furthermore, in the above described present embodiment, the lightsuperimposing means of the present invention has the lens arrays 122 and123. However, the present invention is not limited to this aspect. Thelight superimposing means of the present invention may have the glassrod 125 or the like as shown in FIG. 6 that is a schematic diagramshowing the configuration of a lighting apparatus of one embodimentaccording to the present invention.

(7) Moreover, in the above described present embodiment, the lightsuperimposing means of the present invention has the relay lenses 121and 124. However, the present invention is not limited to this aspect.The light superimposing means of the present invention may have a mirroror a plurality of combined single lenses or may have no such opticalelements (depending on the configuration of the optical system).

(8) Furthermore, the lighting apparatus of the present invention mayfurther comprise light intensity distribution measuring means ofmeasuring the intensity distribution of light superimposed by the lightsuperimposing means. Then, the position of the light reflecting andsynthesizing means may be changed on the basis of the result of themeasurement.

More specifically, as shown in FIG. 7 that is a schematic diagramshowing the configuration of a lighting apparatus of one embodimentaccording to the present invention, the lighting apparatus of thepresent embodiment may comprise light intensity distribution measuringmeans 102 having a plurality of light sensors two-dimensionally arrangedat a position equivalent to that of the light receiving section 110, tomeasure the quantity of light proportional to the quantity of light inthe central and peripheral portions of the light receiving section 110by using a half mirror 101. Then, the synthetic mirror section adjustingmechanism 140 may utilize an actuator (not shown) to change the positionof the synthetic mirror section 130 on time in accordance with thepreviously described result of the light quantity measurement usingautomatic adjustment or manual adjustment based on the user's manualoperation.

Of course, the intensity distribution of light in the light receivingsection 110 may be measured by utilizing means other than the halfmirror 101 and the light intensity distribution measuring means 102instead of utilizing the light intensity distribution measuring means102 arranged to split the optical path using the half mirror 101.

More specifically, the intensity distribution of light in the lightreceiving section 110 may be measured as a light intensity distributionnear the light receiving section 110 or as a light intensitydistribution on the screen in the case where a projection lens(described later) is used to project an image on a light modulatingelement (described later).

(9) Furthermore, the lighting apparatus of the present invention mayfurther comprise light rotating means of rotating light reflected by thelight reflecting and synthesizing means.

(10) Moreover, the lighting apparatus of the present invention mayfurther comprise one or more image display devices (for example, atransmission type liquid crystal panel, a transmission type light bulb,a reflection type light bulb, a mirror panel that can change areflecting direction using arrayed micromirrors, or a light modulatingelement based on an optical write method).

More specifically, the lighting apparatus of the present embodiment maycomprise a transmission type liquid crystal panel 103 as shown in FIG. 8that is a schematic diagram showing the configuration of a lightingapparatus of one embodiment according to the present invention.

(11) Furthermore, the lighting apparatus of the present invention mayfurther comprise an optical element (for example, a prism, a filter, ora mirror) for color separation or synthesis.

(12) Moreover, the lighting apparatus of the present invention mayfurther comprise a projection lens that implements projection typedisplay apparatus for projective display.

More specifically, the lighting apparatus of the present embodiment mayfurther comprise a projection lens 104 that provides projective displayon a projection surface 105 as shown in FIG. 8.

A lighting apparatus comprising an image display device such as atransmission type liquid crystal panel and a projection lens asdescribed above is often called a projection type display apparatus.

EMBODIMENT 2

First, with reference to mainly FIG. 9 that is a diagram illustrating aprojection type display apparatus of Embodiment 2 according to thepresent invention and projective display provided by the projection typedisplay apparatus, the projection type display apparatus of the presentembodiment will be described.

The projection type display apparatus of the present embodimentcomprises nine projection type display apparatuses 200 configuredsimilarly to the above described lighting apparatus of the presentembodiment.

However, as described previously, the projection type display apparatus200 comprises an image display device such as a transmission type liquidcrystal panel and a projection lens.

In the present embodiment, the synthetic mirror section adjustingmechanism 140 (see FIG. 1) of each projection type display apparatus 200is means that can change the position of the synthetic mirror section130 (see FIG. 1) utilizing rotative movement that is a combination of(a) such parallel movement as keeps the bottom surface of the prism 131(see FIG. 1) parallel with the plane containing the optical axis of thelamp unit section 150 (see FIG. 1) and the optical axis of the lightingunit section 120 (see FIG. 1) and (b) such movement as inclines thebottom surface of the prism 131 relative to the plane containing theoptical axis of the lamp unit section 150 and the optical axis of thelighting unit section 120.

The projection type display apparatus of the present embodimentcorresponds to the lighting apparatus system of the present invention.

Now, with reference to mainly FIGS. 1 and 9, description will be givenof operations of the projection type display apparatus of the presentembodiment.

Description will be given below of an operation of the synthetic mirrorsection adjusting mechanism 140 (see FIG. 1) which operation ischaracteristic of the operation of the projection type display apparatusof the present embodiment.

The synthetic mirror section adjusting mechanism 140 (see FIG. 1) ofeach projection type display apparatus 200 drives the synthetic mirrorsection 130 (see FIG. 1) utilizing rotative movement that is acombination of (a) such parallel movement as keeps the bottom surface ofthe prism 131 (see FIG. 1) parallel with the plane containing theoptical axis of the lamp unit section 150 (see FIG. 1) and the opticalaxis of the lighting unit section 120 (see FIG. 1) and (b) such movementas inclines the bottom surface of the prism 131 relative to the planecontaining the optical axis of the lamp unit section 150 and the opticalaxis of the lighting unit section 120.

Such a position change executed by the synthetic mirror sectionadjusting mechanism 140 (see FIG. 1) adjusts the position of thesynthetic mirror section 130 (see FIG. 1) of each projection typedisplay apparatus 200 so that a central portion of the entire 3×3multiscreen 500 is brightest, while its peripheral portion is darkest.

More specifically, the position of the synthetic mirror section 130 ofeach projection type display apparatus 200 is adjusted so that in theentire 3×3 multiscreen 500, (1) the brightness distribution in thedirection of the vertical axis is shaped like a mountain having one peakin a central portion as shown in a graph 501, while (2) the brightnessdistribution in the direction of the horizontal axis is shaped like amountain having one peak in a central portion as shown in a graph 502.

For example, description will be given of the projection type displayapparatus 200 located at the rightmost (arrow X points rightward) anduppermost (arrow Y points upward) position relative to the multiscreen500. The position of the synthetic mirror section 130 is adjusted sothat a corresponding small screen has the brightest part in its lowerleft portion and the darkest part in its upper right portion. For theprojection type display apparatus 200 located at the leftmost andlowermost position relative to the multiscreen 500, the position of thesynthetic mirror section 130 is adjusted so that a corresponding smallscreen has the brightest part in its upper right portion and the darkestpart in its lower left portion.

Thus, high-grade display is realized so that a luminance gradientextends from the central to peripheral portion in the entire 3×3multiscreen 500 with the maximum value present in the central portion.

A program of the present invention allows a computer to execute thefunctions of all or some means (or devices, elements, or the like) ofthe above described lighting apparatus and lighting apparatus system ofthe present invention, and cooperates with the computer.

Alternatively, a program of the present invention allows a computer toexecute the operations of all or some steps (or processes, operations,action, or the like) of the above described lighting method of thepresent invention, and cooperates with the computer.

A recording medium of the present invention carries a program allowing acomputer to execute the functions of all or some the means (or devices,elements, or the like) of the above described lighting apparatus andlighting apparatus system of the present invention so that the programthat can be read and has been read by the computer cooperates with thecomputer in executing the functions.

Alternatively, a recording medium of the present invention carries aprogram allowing a computer to execute the operations of all or somesteps (or processes, operations, action, or the like) of the abovedescribed lighting method of the present invention so that the programthat can be read and has been read by the computer cooperates with thecomputer in executing the functions.

The expression “some means (or devices, elements, or the like) ” as usedherein means one or some of the plural means. The expression “some steps(or processes, operations, action, or the like)” as used herein meansone or some of the plural steps.

Furthermore, the expression “functions of the means (or devices,elements, or the like) ” as used herein means all or some functions ofthe means. The expression “operations of the steps (or processes,operations, action, or the like) means all or some operations of thesteps. In one aspect, the program of the present invention may berecorded in a recording medium that can be read by a computer and maycooperate with the computer.

Alternatively, in one aspect, the program of the present invention maybe transmitted through a transmission medium, read by a computer, andcooperate with it.

Furthermore, the recording medium includes a ROM, and the transmissionmedium includes the Internet or light, electric waves, or sound waves.

Moreover, the above described computer of the present invention is notlimited to pure hardware such as a CPU. It may include firmware, an OS,or peripheral equipment.

As described above, the arrangement of the present invention may beimplemented as software or hardware.

Industrial Applicability

As is apparent from the above description, the present invention has theadvantage of being able to improve the display quality of projectivedisplay.

1. A lighting apparatus comprising: a plurality of light sourcesgenerating light; light reflecting and synthesizing means of reflectingand synthesizing lights generated by all or some of said plurality oflight sources; and light reflecting and synthesizing means holding meansof holding said light reflecting and synthesizing means so that aposition of said light reflecting and synthesizing means can be changedso as to adjust reflecting optical paths of said reflected lights. 2.The lighting apparatus according to claim 1, further comprising lightsuperimposing means of superimposing said reflected lights on eachother, and light intensity distribution measuring means of measuringintensity distribution of said superimposed light, wherein saidadjustment is carried out on the basis of a result of said measurement.3. The lighting apparatus according to claim 1, further comprising lightrotating means of rotating said reflected lights.
 4. The lightingapparatus according to claim 1, wherein said light reflecting andsynthesizing means is constructed utilizing a prism or a mirror.
 5. Thelighting apparatus according to claim 2, wherein said lightsuperimposing means is constructed utilizing a lens array or a glassrod.
 6. A lighting apparatus system comprising a plurality of lightingapparatuses according to claim 1, wherein the position of said lightreflecting and synthesizing means of each of the lighting apparatuses ischanged so as to meet a predetermined relationship.
 7. A lighting methodcomprising: a step of generating lights from a plurality of lightsources, a light reflecting and synthesizing holding step of holdingreflected and synthesized lights generated by all or some of said lightsources so as to adjust reflecting optical paths of said reflectedlights; and a reflecting optical path adjusting step of adjusting thereflecting optical paths of said reflected lights.
 8. A lighting methodaccording to claim 7, further comprising a light superimposing step ofsuperimposing said reflected lights on each other, and a light intensitydistribution measuring step of measuring intensity distribution of saidsuperimposed lights, wherein said adjustment is carried out on the basisof a result of said measurement.
 9. A program allowing a computer toexecute the reflecting optical path adjusting step of the lightingmethod according to claim
 7. 10. A recording medium carrying the programaccording to claim 9 wherein the recording medium can be processed by acomputer.